/Engine/Source/Editor/AnimationBlueprintEditor/Public/AnimationNodes/SAnimationGraphNode.h
Override this to add widgets below the pins but above advanced view arrow.
virtual void CreateBelowPinControls ( [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [SVerticalBox](API\Runtime\SlateCore\Widgets\SVerticalBox) > MainBox )